Earlier today, I noticed that my 96 Saturn SL2's brake pedal must travel to the floor before I have significant engagement.
This isn't the first time that I have had this problem. It had happened back in May 2009, but not with the same severeity. At that time, I just ignored the problem and it somehow went away on its own. I'm not sure what happened, but the pedal just firmed up one day and stayed that way until this morning.
Also, if I hold the brake pedal at a stop light, it does NOT drop. If I push and hold the pedal with the car off, it doesn't drop either. I pressure bled the system back in June 2008, so I don't think air is the problem. In fact, it would be odd for the pedal to be firm sometimes and soft at other times if I had air in the system, right?
So what should I do? I'm not sure how-to fix this. All of my brake pads appear to be wearing evenly. I do not see any brake fluid leaks.
Should I replace the master cylinder? If so, what brand? Raybestos or A1 Cardone? If I replace the master cylinder, how am I going to bleed the brake system? I do have ABS.
Thanks in advance!
P.S. Master Cylinder replacement is a big job on this car:
Quote:
REMOVAL & INSTALLATION
CAUTION
The ABS modulator pistons are normally in the HOME or top position. In this position, the modulator drive gears are under spring tension and will turn during disassembly if not unloaded. The sudden rotation of gears and release of tension could cause injury if done without extreme care. It is recommended that the pistons be run down and the tension released prior to removing the brake control assembly, if the unit is to be disassembled.
If removing the unit for disassembly, connect the Saturn Portable Diagnostic Tool (PDT), or an equivalent scan tool, and perform the RUN ABS MOTORS, PISTONS DOWN-REL test to run the modulator pistons down and release spring tension.
Remove the air cleaner/induction assembly.
Disconnect the negative battery cable, then remove the battery box and battery from the vehicle.
Tag and unplug the 2 electrical connectors from the solenoids and the connector from the brake fluid level sensor on the lower side of the fluid reservoir.
Remove the CPA device from the motor pack 6-way connector and disengage the connector from the bottom of the motor pack.
Position a cloth to catch any escaping fluid, then tag and disconnect the brake lines from the control assembly. Plug the openings to prevent excessive fluid contamination or loss.
WARNING
Once the brake lines are disconnected, do not excessively pull or bend the lines away from the module, or the lines may be damaged.
Remove the 2 brake control assembly-to-brake booster retaining nuts and remove the assembly.
If necessary, disassemble the unit as follows:
Remove the 6 gear cover Torx® screws from the bottom of the assembly and remove the cover. If the entire motor pack assembly is being replaced, skip to Step C, and then to the assembly procedure.
Mark the location of the modulator drive gears for reassembly. Insert a small suitable prybar between the holes in the gears to keep them from moving and remove the 3 gear-to-driveshaft retaining nuts. Remove the gears from the modulator.
WARNING
Do not allow the gears to turn while removing the driveshaft nuts, or the piston may hit the top of the modulator bore and damage the pistons.
Remove the motor pack-to-modulator Torx® screws and separate the motor pack from the modulator.
Remove the 2 modulator-to-master cylinder through-bolts and separate the master cylinder from the assembly.
Remove the 2 transfer tubes and O-rings from the master cylinder and modulator.
Remove the through-bolt O-rings from the master cylinder and modulator.
To install:
If necessary, assemble the ABS control unit as follows:
Lubricate the new transfer tube O-rings with clean brake fluid. Press the NEW tubes and O-rings into the modulator by hand until fully bottomed.
Lubricate the new through-bolt O-rings with clean fluid and install the rings into the master cylinder and modulator.
Install the master cylinder onto the modulator, and press the transfer tubes into position on the master cylinder.
Install the through-bolts and tighten to 146 inch lbs. (16.5 Nm).
Position the drive gears onto the driveshafts as noted earlier. Hold the gears from turning and tighten the retaining nuts to 75 inch lbs. (8.5 Nm).
Hold the modulator upside down with the gears facing you and carefully rotate each gear counterclockwise until movement stops. This will position the pistons close to the top or HOME position and simplify the bleeding procedure.
Position the motor pack to the modulator, aligning the gears, and install the 4 motor pack retaining screws. Tighten the screws to 40 inch lbs. (4.5 Nm).
Install the gear cover onto the modulator assembly with the 6 retaining screws, then tighten the screws to 20 inch lbs. (2.25 Nm).
Position the control assembly onto the brake booster studs, then install the retaining nuts and tighten to 20 ft. lbs. (27 Nm).
Position the brake lines into the control assembly as originally noted and tighten the fittings to 24 ft. lbs. (32 Nm).
NOTE: From the front of the master cylinder moving rearward, the lines are: LF, RR, LR and RF.
Install the 6-way wiring harness connector and insert the CPA device. Install the wiring harness connectors to the brake fluid level and 2 solenoid valve electrical connectors.
Install the battery and hold-down device. Connect the positive battery cable first, then the negative battery cable.
Install the air cleaner/induction assembly
This isn't the first time that I have had this problem. It had happened back in May 2009, but not with the same severeity. At that time, I just ignored the problem and it somehow went away on its own. I'm not sure what happened, but the pedal just firmed up one day and stayed that way until this morning.
Also, if I hold the brake pedal at a stop light, it does NOT drop. If I push and hold the pedal with the car off, it doesn't drop either. I pressure bled the system back in June 2008, so I don't think air is the problem. In fact, it would be odd for the pedal to be firm sometimes and soft at other times if I had air in the system, right?
So what should I do? I'm not sure how-to fix this. All of my brake pads appear to be wearing evenly. I do not see any brake fluid leaks.
Should I replace the master cylinder? If so, what brand? Raybestos or A1 Cardone? If I replace the master cylinder, how am I going to bleed the brake system? I do have ABS.
Thanks in advance!
P.S. Master Cylinder replacement is a big job on this car:
Quote:
REMOVAL & INSTALLATION
CAUTION
The ABS modulator pistons are normally in the HOME or top position. In this position, the modulator drive gears are under spring tension and will turn during disassembly if not unloaded. The sudden rotation of gears and release of tension could cause injury if done without extreme care. It is recommended that the pistons be run down and the tension released prior to removing the brake control assembly, if the unit is to be disassembled.
If removing the unit for disassembly, connect the Saturn Portable Diagnostic Tool (PDT), or an equivalent scan tool, and perform the RUN ABS MOTORS, PISTONS DOWN-REL test to run the modulator pistons down and release spring tension.
Remove the air cleaner/induction assembly.
Disconnect the negative battery cable, then remove the battery box and battery from the vehicle.
Tag and unplug the 2 electrical connectors from the solenoids and the connector from the brake fluid level sensor on the lower side of the fluid reservoir.
Remove the CPA device from the motor pack 6-way connector and disengage the connector from the bottom of the motor pack.
Position a cloth to catch any escaping fluid, then tag and disconnect the brake lines from the control assembly. Plug the openings to prevent excessive fluid contamination or loss.
WARNING
Once the brake lines are disconnected, do not excessively pull or bend the lines away from the module, or the lines may be damaged.
Remove the 2 brake control assembly-to-brake booster retaining nuts and remove the assembly.
If necessary, disassemble the unit as follows:
Remove the 6 gear cover Torx® screws from the bottom of the assembly and remove the cover. If the entire motor pack assembly is being replaced, skip to Step C, and then to the assembly procedure.
Mark the location of the modulator drive gears for reassembly. Insert a small suitable prybar between the holes in the gears to keep them from moving and remove the 3 gear-to-driveshaft retaining nuts. Remove the gears from the modulator.
WARNING
Do not allow the gears to turn while removing the driveshaft nuts, or the piston may hit the top of the modulator bore and damage the pistons.
Remove the motor pack-to-modulator Torx® screws and separate the motor pack from the modulator.
Remove the 2 modulator-to-master cylinder through-bolts and separate the master cylinder from the assembly.
Remove the 2 transfer tubes and O-rings from the master cylinder and modulator.
Remove the through-bolt O-rings from the master cylinder and modulator.
To install:
If necessary, assemble the ABS control unit as follows:
Lubricate the new transfer tube O-rings with clean brake fluid. Press the NEW tubes and O-rings into the modulator by hand until fully bottomed.
Lubricate the new through-bolt O-rings with clean fluid and install the rings into the master cylinder and modulator.
Install the master cylinder onto the modulator, and press the transfer tubes into position on the master cylinder.
Install the through-bolts and tighten to 146 inch lbs. (16.5 Nm).
Position the drive gears onto the driveshafts as noted earlier. Hold the gears from turning and tighten the retaining nuts to 75 inch lbs. (8.5 Nm).
Hold the modulator upside down with the gears facing you and carefully rotate each gear counterclockwise until movement stops. This will position the pistons close to the top or HOME position and simplify the bleeding procedure.
Position the motor pack to the modulator, aligning the gears, and install the 4 motor pack retaining screws. Tighten the screws to 40 inch lbs. (4.5 Nm).
Install the gear cover onto the modulator assembly with the 6 retaining screws, then tighten the screws to 20 inch lbs. (2.25 Nm).
Position the control assembly onto the brake booster studs, then install the retaining nuts and tighten to 20 ft. lbs. (27 Nm).
Position the brake lines into the control assembly as originally noted and tighten the fittings to 24 ft. lbs. (32 Nm).
NOTE: From the front of the master cylinder moving rearward, the lines are: LF, RR, LR and RF.
Install the 6-way wiring harness connector and insert the CPA device. Install the wiring harness connectors to the brake fluid level and 2 solenoid valve electrical connectors.
Install the battery and hold-down device. Connect the positive battery cable first, then the negative battery cable.
Install the air cleaner/induction assembly
